Athletes and Sports Enthusiasts: Are You Getting Enough Calories?

December 30, 2018 , ,

Do you practice an average of at least 60 minutes of exercise per day? Have you suffered from stress fractures? Have you lost weight unintentionally? Do you often feel that you are tired or lack energy? Are you often hungry? If you are a female athlete, have you missed your period for 3 months or more? If you answered yes to any of these questions, you may not be getting enough calories in relation to your energy expenditure. Insufficient caloric intake can have serious consequences on the health of athletes (both men and women) including an increased risk of injuries and infections, a decrease in bone mineral density and subsequently an increased risk of stress fractures, micronutrient deficiencies such as iron and calcium and decreased sports performance. It should be noted that the prevalence of eating disorders is higher among athletes than non-athletes and has been on the rise for the past two decades.

The absence of menstruation is a common condition among women athletes but is often ignored and considered to be a normal result of intensive training. It is, however, often caused by an insufficient energy intake that can have serious health consequences. The female athlete triad is first defined by three criteria: an insufficient energy intake, a decrease in bone mineral density, and the absence of menstruation for 3 months or more. On the other hand, it is not only female athletes who are affected. In fact, insufficient caloric intake can increase the risk of fractures and affect the hormones (a decrease in testosterone level) in male athletes as well. This is why the Relative Energy Deficiency in Sports (RED-S) is a new terminology that encompasses the female athlete triad as well as the recognition of this problem in male athletes.

A study of 59 elite athletes (16 of whom participated in the Rio Olympics) revealed that athletes with RED-S have a 4.5 times higher risk of developing a stress fracture. Even a caloric deficit of only 300 calories a day can have a big impact on long-term health. Thus, if your training volume is high and you want to lose weight, it is important to aim for slow weight loss with a low caloric deficit per day, and only over a short period of time. Ideally, one should avoid aiming for weight loss by creating an energy deficiency during competition and intensive training phases. It should be noted that even if your weight is stable, it is still possible that you are not eating enough calories and that your risk of injuries, infections, and nutritional deficiencies is increased. Indeed, by being energy deficient, the body adapts and decreases its resting metabolism, which means that you will expend fewer calories at rest. In the long run, this can negatively affect your ability to control your body weight.

RED-S can be detected in women when they stop menstruating. In men, a good indicator is a low testosterone level, which can be detected via a blood test. A normal testosterone level in men is between 10 and 30 nmol/L. Another sign of RED-S is a decrease in sexual desire.

If you suspect that you have RED-S, here are some tips for increasing your caloric intake:

  • Add snacks between your meals that contain both carbohydrate and protein such as a fruit with nuts, rice cakes with nut butter, crackers with cheese, or yogurt with fruit.
  • Add a smoothie to your daily diet that contains protein (protein powder, yogurt, tofu or cow or soy milk) and fruits.
  • Add good fats to your diet such as ground flaxseeds or chia seeds, nuts, olive oil and avocados.
  • Don’t hesitate to get help from a Sports Dietitian who can help you determine your caloric needs, analyze your diet, advise and build a personalized meal plan for you. You can also visit to receive a personalized menu according to your energy expenditure. The Sports meal plan has a portion calculator that allows you to adjust your caloric intake based on your age, gender, weight, height and physical activity level.


  • Burke et Deakin (2015) Clinical Sports Nutrition, 5th Edition, McGraw-Hill Education, 828 pages.
  • Mountjoy et coll. (2018) International Olympic Committee (IOC) Consensus Statement on Relative Energy Deficiency in Sport (RED-S): 2018 Update. Int J Sport Nutr Exerc Metab 28(4):316-331.
  • Heikura et coll. (2018) Low Energy Availability Is Difficult to Assess but Outcomes Have Large Impact on Bone Injury Rates in Elite Distance Athletes. Int J Sport Nutr Exerc Metab; 28:403-411.


Kathryn Adel
Kathryn completed degrees in kinesiology and nutrition, as well as a Masters in Sports Nutrition. She is a member of OPDQ and of the Academy of Nutrition and Dietetics. She ran track and cross-country at a national level. Kathryn specializes in sports nutrition, weight loss, diabetes, as well as heart and gastrointestinal health. Kathryn is experienced with the low FODMAP diet and she completed the Monash University low FODMAP dietitian's training.

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